Removed unnecesary PackageReference for test project

Author: sesispla

tests/tests.csproj

@@ -4,9 +4,6 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Rest.ClientRuntime" Version="3.0.3" />
-    <PackageReference Include="Newtonsoft.Json" Version="10.0.2" />
-    <PackageReference Include="YamlDotNet.NetCore" Version="1.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
     <PackageReference Include="xunit" Version="2.3.0-beta3-build3705" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.0-beta3-build3705" />